aluminum alloy for bridge deck and wave breaker load calculations

I am building a bridge deck with wave breaker and cabin with integrated furniture using aluminum using 4 and 5mm sheet and flat bar with pulse mig welding.

I'm not sure what 5000 alloy to use on the sheet and wondered where 6000 may be best used. Any comment on wire size and alloy also apreciated.

Also confused as to how to approach the pressure loading calculations on the wave breaker. should I consider the total weight of the boat slamming and over what about of the structure and is there a dynamic factor to add also? I have a lot of clearance 5% but the old molded understructure had pockets that concentrated wave energy.

I'm planning a two arches design and will roll the shape into the bottom surface sheet and weld onto frames with a welded deck above.

 

Hi Riskmore,

Well, firstly too many issues at once.
Thus what is the main priority, the alloy or the design?

I would suggest you focus on the design aspect first. As such, do you have any dwgs and data to assist?